3,816 research outputs found
Exact low-energy effective actions for hypermultiplets in four dimensions
We consider the general hypermultiplet Low-Energy Effective Action (LEEA)
that may appear in quantized, four-dimensional, N=2 supersymmetric, gauge
theories, e.g. in the Coulomb and Higgs branches. Our main purpose is a
description of the exact LEEA of n magnetically charged hypermultiplets. The
hypermultiplet LEEA is given by the N=2 supersymmetric Non-Linear Sigma-Model
(NLSM) with a 4n-dimensional hyper-K"ahler metric, subject to non-anomalous
symmetries. Harmonic Superspace (HSS) and the NLSM isometries are very useful
to constrain the hyper-K"ahler geometry of the LEEA. We use N=2 supersymmetric
projections of HSS superfields to N=2 linear (tensor) O(2) and O(4) multiplets
in N=2 Projective Superspace (PSS) to deduce the explicit form of the LEEA in
some particular cases. As the by-product, a simple new classification of all
multi-monopole moduli space metrics having su(2)_R symmetry is proposed in
terms of real quartic polynomials of 2n variables, modulo Sp(n)
transformations. The 4d hypermultiplet LEEA for n=2 can be encoded in terms of
an elliptic curve.Comment: 60 pages, LaTeX, macros included, references adde
The Intermediate Coupling Regime in the AdS/CFT Correspondence
The correspondence between the 't Hooft limit of N=4 super Yang-Mills theory
and tree-level IIB superstring theory on AdS(5)xS(5) in a Ramond-Ramond
background at values of lambda=g^2 N ranging from infinity to zero is examined
in the context of unitarity. A squaring relation for the imaginary part of the
holographic scattering of identical string fields in the two-particle channels
is found, and a mismatch between weak and strong 't Hooft coupling is pointed
out within the correspondence. Several interpretations and implications are
proposed.Comment: 10 pages, LaTeX, reference adde
A Calibrated Olfactory Display for High Fidelity Virtual Environments
Olfactory displays provide a means to reproduce olfactory stimuli for use in virtual environments. Many of the designs produced by researchers, strive to provide stimuli quickly to users and focus on improving usability and portability, yet concentrate less on providing high levels of accuracy to improve the fidelity of odour delivery. This paper provides the guidance to build a reproducible and low cost olfactory display which is able to provide odours to users in a virtual environment at accurate concentration levels that are typical in everyday interactions; this includes ranges of concentration below parts per million and into parts per billion. This paper investigates build concerns of the olfactometer and its proper calibration in order to ensure concentration accuracy of the device. An analysis is provided on the recovery rates of a specific compound after excitation. This analysis provides insight into how this result can be generalisable to the recovery rates of any volatile organic compound, given knowledge of the specific vapour pressure of the compound
Bronchiectasis insanity:Doing the same thing over and over again and expecting different results?
Bronchiectasis is an increasingly common disease with a significant impact on quality of life and morbidity of affected patients. It is also a very heterogeneous disease with numerous different underlying etiologies and presentations. Most treatments for bronchiectasis are based on low-quality evidence; consequently, no treatments have been approved by the US Food and Drug Administration or the European Medicines Agency for the treatment of bronchiectasis. The last several years have seen numerous clinical trials in which the investigational agent, thought to hold great promise, did not demonstrate a clinically or statistically significant benefit. This commentary will review the likely reasons for these disappointing results and a potential approach that may have a greater likelihood of defining evidence-based treatment for bronchiectasis
Absolute Present, Zen and Schrödingerâs One Mind
Erwin Schrödinger holds a prominent place in the history of science primarily due to his crucial role in the development of quantum physics. What is perhaps lesser known are his insights into subject-object duality, consciousness and mind. He documented himself that these were influenced by the Upanishads, a collection of ancient Hindu spiritual texts. Central to his thoughts in this area is that Mind is only One and there is no separation between subject and object. This chapter aims to bridge Schrödingerâs view on One Mind with the teachings of DĆgen, a twelfth century Zen master. This bridge is formed by addressing the question of how time relates to One Mind, and subject-object duality. Schrödinger describes the experience of One Mind to be like a timeless now, whereas subject-object duality involves a linear continuum of time. We show how these differing positions are unified in the notion of âabsolute presentâ, which was put forward in the philosophy of Nishida KitarĆ (1871â1945). In addition, we argue that it is in this notion of absolute present that the views of Schrödinger, DĆgen and Nishida meet
Cubic Twistorial String Field Theory
Witten has recently proposed a string theory in twistor space whose
D-instanton contributions are conjectured to compute N=4 super-Yang-Mills
scattering amplitudes. An alternative string theory in twistor space was then
proposed whose open string tree amplitudes reproduce the D-instanton
computations of maximal degree in Witten's model.
In this paper, a cubic open string field theory action is constructed for
this alternative string in twistor space, and is shown to be invariant under
parity transformations which exchange MHV and googly amplitudes. Since the
string field theory action is gauge-invariant and reproduces the correct cubic
super-Yang-Mills interactions, it provides strong support for the conjecture
that the string theory correctly computes N-point super-Yang-Mills tree
amplitudes.Comment: 19+1 pages, 4+1 EPS figures, JHEP3 LaTeX; v2: minor corrections,
references added; v3: the final version published in JHEP with a new footnote
on the d=0 on-shell contributio
Event Rates, Hospital Utilization, and Costs Associated with Major Complications of Diabetes: A Multicountry Comparative Analysis
Philip Clarke and colleagues examined patient-level data for over 11,000 participants with type 2 diabetes from 20 countries and find that major complications of diabetes significantly increased hospital use and costs across settings
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